A Reminder About Your Heart
Yes - you are free to store up as many treasures as you like in your heart. It is your heart, after all. Cram it with memories - good or bad. Select people who belong there. Choose stuff and put it there, too. Seriously - whatever and whoever you want to store up in your heart is fair game.
But please remember that space is limited. You cannot possibly hold everything.
Choice is hard, but it is necessary. The things that stay in your heart, then, must be really important.
And that should tell you something about who and what is allowed in.